Today, much work is performed by automatic machines, such as an automatic sales machine, to offset the increase in manpower costs. Initially, the automatic sales machine only received coins. Characteristics of a coin, such as, for example, volume, density, and electric conductivity, are used to determine whether the coins are real or counterfeit. However, when the paper money with high face value is commonly used, such sales machines must receive paper money.
Typically, a money exchange apparatus is installed in an automatic sales machine for receiving paper money. When the paper money is inserted into the entrance and blocks a light set in the entrance, a main roller is triggered to bring the paper money into the money exchange apparatus. An optical detection apparatus is also triggered to detect the paper money for determining whether the paper money is real or counterfeit. Each optical detection apparatus includes some light-emitting diodes (LEDs) that emit infrared rays and visible light with different wavelengths and photodiodes for receiving the emitted light from LEDs. These LEDs and photodiodes are used to detect the characteristics of the paper money, such as the reflection ratio, transmission ratio and fluorescent color, for determining whether the money is real or counterfeit and the face value of the paper money.
The main object of using an automatic sales machine is for reducing manpower costs and to allow off-hour business. However, the inserted paper money is often extracted from the money exchange apparatus by a criminal using a special tool in off-hours. Therefore, preventing extraction of paper is very important.
FIG. 1 is a schematic, three-dimensional diagram of a conventional money exchange apparatus with paper money inserted therein. First, the paper money 100 is sent to the entrance and through the trail 102 into the money exchange apparatus. Then, a curved trail 104 is used to lead the paper money 100 to prevent extraction of the paper money 100. An optical detecting apparatus 106 connected to the curved trail 104 detects the veracity of the paper money 100. Real paper money 100 is sent to the storage box 108, and counterfeit paper money 100 is sent out of the money exchange apparatus through another route (not shown in this figure) or through the original route.
Typically, the curved trail 104 is used to avoid extraction of the paper money 100. However, this kind of protection is easily circumvented. For example, a criminal may first adhere a line to a real bill. A counterfeit bill is inserted into the money exchange apparatus after inserting the real bill. Then, the real bill may be extracted from the money exchange apparatus by this line immediately when the counterfeit bill is rejected by the money exchange apparatus. Therefore, although the counter in the money exchange apparatus counts receipt of a bill, the bill has actually been extracted by the criminal. At this time, if the criminal asks money exchange apparatus to return this sum of money, money from the storage box is returned to the criminal, resulting in a business loss. Therefore, a design that can completely prevent loss is required.